Laboratory Studies of the Kinetics and Photochemistry of Hydrogen Oxides (HOx) Cycling in the Lower Atmosphere

University Of Miami, Coral Gables FL

Investigators

Abstract

This work is focused on areas of current uncertainty in the chemical cycling of OH and HO2 (HOx) radicals in the troposphere. The project combines laser-based diagnostic techniques with novel experimental approaches to study the kinetics and photochemistry of several elementary processes that contribute to the production, loss, and cycling of Hydrogen oxides (HOx). These processes will be isolated and studied under realistic atmospheric conditions to the fullest extent possible. The specific areas of investigation are: 1) Kinetics and photochemistry of formaldehyde and acetone. 2) The detailed mechanism of the recombination of hydroxyl radical (OH) with nitrogen dioxide (NO2) under atmospheric conditions, including the use of a photofragment laser-induced fluorescence (LIF) scheme to directly monitor peroxynitrous acid (HOONO), together with conventional LIF detection of OH. 3) The quantum yield of oxygen atom (O1D) production from the photolysis of ozone between 290 and 411 nm. 4) Kinetics and mechanisms of the reaction of OH with propene and isoprene, including measurement of the formaldehyde yield for these reactions. The broader scientific impacts of the research include progress in understanding of the oxidizing capacity of the atmosphere, with important implications in areas such as climate and urban pollution. In addition, students at the postdoctoral, graduate, and high school level will have opportunities to learn through research about experimental atmospheric chemistry.